Stability control systems do look at your steering input and consider that in conjunction with loss of traction and data from yaw rate sensors in an understeer situation and decrease power or apply brake(s) for the car to regain traction and directional stability.

Yeah, I have personal experience. On the skid pad I was able to produce very serious understeer, to the point where the tires were scrubbing and the car was essentially pushing straight out of the radius. I did it with DSC on.